<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <title></title>
    <style>
    .father {
      width: 80%;
      height: 100px;
      background-color: pink;
      display: flex;
      margin: 0 auto;
    }
    .son:nth-child(2n+1) {
      background-color: red;
      width: 50px;
    }
    .son:nth-child(2) {
      background-color: orange;
      flex: 1;
    }
    </style>
    <link href="css/style.css" rel="stylesheet">
  </head>
  <body>
  <div class="father">
      <div class="son">1</div>
      <div class="son">22</div>
      <div class="son">3</div>
    </div>
  </body>
</html>
